JERUSALEM, Israel -- Israel cannot depend on the U.S. to take the lead against the Iranian nuclear program, Israeli Defense Minister Moshe Ya'alon said Tuesday.

His remarks came just as the P5+1 (U.S., U.K., France, Russia, China and Germany) are about to begin the next round of talks on Iran's nuclear facilities.

The U.S. should be leading the campaign against Iran, Ya'alon said, but instead it's making deals with it. Israel will do what it must to defend itself.

"We thought that the one who needs to lead the campaign against Iran is the U.S.," the defense minister said during remarks at Tel Aviv University earlier this week, the Israeli daily Ha'aretz reported.

"If we wished others would do the work for us, it wouldn't be done soon and therefore in this matter, we have to behave as if we can only rely on ourselves," Ya'alon said.

U.S. influence around the world is declining, he said, as the crisis in the Ukraine shows. Russian President Vladimir Putin seems unimpressed with President Obama's warnings.

"Weakness certainly does not pay in the world," he said. "No one can replace the U.S. as the world's policeman. I hope the U.S. will come to its senses."